1. Technical Field
Example embodiments of the present invention relate in general to a wireless communication technology, and more specifically, to a method for transmitting data in a communication system including at least one relay base station, and an apparatus for the same.
2. Related Art
Generally, a communication system including a relay base station may comprise a central base station, at least one relay base station, and at least one terminal. The terminal may perform communications as it is connected to an upper central base station or an upper relay base station. The relay base station may provide communication services to lower terminals as it is connected to an upper central base station or an upper other relay base station. The central base station may be connected to a core network through a backhaul.
When such the communication system operates in a frequency division duplexing (FDD) manner, a central base station, a relay base station, and a terminal may use F0 as uplink carrier frequency or downlink carrier frequency, and use F1 as downlink carrier frequency or uplink carrier frequency.
For example, the central base station may use F0 as downlink frequency resource and F1 as uplink frequency resource. On the contrary, a lower relay base station connected to the central base station may use F0 as uplink frequency resource and F1 as downlink frequency resource. The terminal connected to the relay base station may use F0 as uplink frequency resource and F1 as downlink frequency resource identically to the relay base station.
Under the above-described environment, a terminal in a state (that is, an active state) of communicating with at least one base station (that is, the central base station or the relay base station) should search both F0 and F1 in order to search neighbor cells for performing handover. However, it is difficult to perform cell-search since a signal which is transmitted through F0 exists as an uplink signal. That is, since there may be collisions between uplink signal and downlink signal which are transmitted through F0, there may be a problem that a terminal cannot acquire a synchronization signal correctly.